Apparatus and procedure for feeding molten glass



F. L. O. WADSWORTH original Filed Marcnls, 1955 APPARATUS AND PROCEDURE FOR FEDINGOLTEN GLASS INVENTOR Patented sept. 12, 1939 UNITED sixilazssrrsna'ro's aan PROCEDURE Fon ING novum `canas FEED- Frank L. 0. Wadsworth, Pittsburgh, Pa., asslgnor to Ball Brothers Company, Muncie, Ind., a corporation oflndiana Application March 15., 1935, Serial No. 11,227 Renewed May 21,1193? 21 Claims.

and shape, such as are required or desirable inconnection with the particular article fabricating procedure or mechanisms employed.

Glass feeders may be divided into two general classes, viz., natural flow feeders in which the molten material isrdelivered from any suitable source of supply in either a continuous or intermittent stream under Ythe action of gravitylalone; and forced iiow` feeders in which the action of l5 gravity is either opposed or aided-or alternately opposed and supplemented-by externally applied forces. Both of these classes of feeders have their own inherent advantages and are extensively used in connection with different forms of fabricating or forming machines. y

One object of 'my invention is to produce a feeder which has the advantages of a natural iiow feedenin which the molten glass is expelled or extruded,v from the feederv orice under the g5 action of gravity alone, but under a` periodically increased gravity head which will` accelerate the extrusion atregular recurrent intervals, without the application of any outside force or pressure on the flowing material.` A procedure such as above outlined enables me to avoid certain dimculties .and disadvantages sometimes encountered with forced flow feeders, where the rate of delivery or vexpulsion of the'moltenmaterial is in large part controlled by externally imposed forces, which may themselves vary in magnitude, and whose action is affected in marked degree by variations in the temperature orother Physical characteristics (viscosity. etc.) of the molten material. e

Another' object of my invention is, to provide a 40 feeder which is of simple 'self-contained construction; is easily controlled in operation; and is readily adjustable to avary itsrate of delivery, for the purpose of obtaining a seriesof uniformly dimensicned mold charges (stream sections) of the desired shape and weicht.

Other objects and purposes of the present invention will be made readily apparait to any.

Fig.'lI is a section taken on the plane II-II of Fig. I: l'

Fig. III is a section taken on the plane III-III of Fig. II;

Fig. IV is a vertical sectionof another feeder 5 illustratingL another exemplication of my invention;

Fig. V is asection taken yon lthe plane V-V of Fig. VI is a developed view of the cam track 10 employed forraising and lowering the air bell;

Fig. V11' is a section taken on the plane VII--VII of Fig. IV; v

Fig. VlJI is a partial view in vertical section illustrating another type of forehearth construcl5 tion;

Fig. IX is a partial sectional elevation illustrating another exempliilcation of my invention; and

Fig. X is a section taken on the plane X-X of The procedure constituting a part of the present invention involves controlling 4the flow of molten glass through a submerged ilow orifice in such a way `as to produce, by a timed severing operation, mold charges of the desired size and 25 weight and of requisite shape to-enter a mold and Vbe effectively processed while in the mold. This `itrroced'ureinvolves the periodic application of a lifting force to the mass of molten glass above the orice, but only for the purpose of momentarily p checking the, ilow therethrough and concurrently increasing the gravity -head of the mass thereabove.

The feeder shown in Figs. I. II and III resembles in some respects the construction illustrated and 85 described in the Hitchcock Patents Nos. 805,067 (Re. No'. 13,929) and 805.068; and toy facilitate the comparison of my improved feeder with that of Hitchcock, I will indicate various parts of the herein described apparatus by the same reference 0) numerals as are employed to designate similar or corresponding members of the Hitchcock patent apparatus. Thus: y

indicates a suitable receptacle, or reservoir,

4 which contains the parentv orsupply body of 4l heated body of insulating material (as described lo by Hitchcock)V orby the body of molten glass in the reservoir itself (as here shown); I is a horizontal eway which leads from the body of glassinthereceptacleltothechamberhlis'a vertlcalconduitltonedotheclv which is 'carried by a suitable bracket I2 that is clamped on one of the vertical side posts I3 of the forehearth frame. 'Ihe lower end of this lever is provided with an anti-friction roller Il and is engaged by a single acting or fone-way" cam Il, which is keyed to a cross shaft I6, that may be driven by any' suitable variable speed motorl (not shown). The upper end of the lever 9 is coupled to the base. or support of the dia- 20 phragm casing 6, by a relatively light spring la,

whose tension is suilicient to overcome the'frictional resistance to the inward or return movement of the lever member 9, and thus maintain the cam elementsy I4-I5 in operative engagement; but this spring cannot act on the connected diaphragm elements 2li--2I-l-1; and cannot therefore produce any mechanical compression of the air in the diaphragm chamber. .,The creation of asuperatmospheric pressure in this chamber-(or in the conduit and chamber 3, connected therewith) from any other cause (e. g. such as a change in temperature therein) is also prevented by the pressure of a light sensitive check valve I8, which is mounted in the rear wall of the diaphragm casing 6, and which is so supported and balanced that it will open whenever the` pressure in the enclosed spaces 3 5-1-6-1 tends to rise to the slightest degree above that of the external air.

When the diaphragm 1 is moved outwardly- (bythe engagement of the cam actuated lever elements S-l, with the rod elements 2li-2|- l-the relief valve I8 is immediately closed, and. held shut, by the partial vacuum that results from the `enlargement of the diaphragm chamber.-

The characteristic -mode of operation of my improved variable head natural ilow feeder will 1 4now be readily understood. The parts are so proportioned and adjusted that at each revolution. of the cam I5 the diaphragm 1- is left free to return, if necessary, to the extreme dotted line position 1'; (where the end of the rod 8 is against Athe rear wall of the diaphragm casing 6) and in this position the level of the glass in the chamber 3 is substantially the same as that in the main supply reservoir |;-this level being determined by the relative rates of free (gravity) lilow through the passageway 2 and the delivery oriilce i8 at the bottom of the chamber 3. As the cam revolves the upper end of the lever 9 moves outwardly and the sleeve I0, comes into engagement with the members 2li-2| i (the time of this engagement being determined by Vthe setting of* these adjustable elements on` the rod 8)'-and the diaphragm 1 is drawn forward to Vcreate a parofthe suction stroke; i. e., by the adjustment of the rod elements 2li-2|. When the high point on the cam I5 passes out from under the cam roller Il, the spring la. immediately draws the sleeve III back out of engagement with the rod 5 elements l2l2|, and leaves the diaphragm 1 free to be returned to a position of dynamic equilibrium by the pressure of the atmosphere on its outer surface. During this phase of operation the glass resumes its free unrestricted flow from 10 the delivery orifice under the action of a progressively decreasing gravity head, without being subjected to the influence of any superimposed external force or pressure, and without being aected by any vartiations or irregularities of action that might result fromchanges in such external influences if they were present.

'I'he period of this free natural gravity flow from the delivery orihce IS-and the accompanying gradual decrease in the gravity head established by the preceding vacuum stroke of the diaphragm pump-is controlled by the' time of revolution of the cam l5; and this may be varied, as previously explained, by the speed of the driv ingmotor. But whatever this period may be the diaphragm 1 will, during this intervaljbe automatically moved inwardly, under the pressure of the external air on its outer surface. so as to maintain a'corresponding atmospheric pressure condition inthe delivery chamber I, independ- 3o ently of the relief action of the check valve I8. The outward movement of the diaphragm 1 is therefore immediately eective in initiating the suction action on the glass in the chamber I, regardless of what the level therein maythen be, and regardless of when or where this outward movement begins; while the range of this outward movement is definitely limited and conincreased, by decreasing the speed of revolution tial vacuumin the upper end (4) of the chamber y 3; and the inflow of glass through the passage 2 is accelerated, while theoutow from the delivery orifice Il is concurrently retarded or ar rested. y, 4

The above described actionresults in a` periodic lifting of the level of the molten material in the 'deliver'ychamberand a corresponding increase in the gravity head or pressure above the delivery outlet; the increase being governed by the range of the cam Il, the glass will fall to a lower level in the chamber 3 (but never substantially below the glass in the main supply chamber I), andthe diaphragm 1 will move inwardly by a corre' spondingly greater amount; so that on the next positive suction stroke the lever sleeve l0 will "pick up" the diaphragm rod element 20-2I at -an earliefpoint in its stroke and, by the increased movement, thus obtained. raise the glass in the chamber l to a correspondingly higher level. If the interval of free gravity owis decreased, (by increasing the speed of the cam Il) the drop of thel glass in the delivery chamber will b'e less, 55 and the inward movement of the diaphragm 1 is reduced, thereby delaying the engagment of the elements I 0 and 20-2I, on the succeeding out- -ward movement 'of the cam actuated lever 9, and

i maximum levenseneadif or the molten :dammi abovev the delivery orifice can never exceed a controlled and predeterminedheight. 0n the other hand, this level can' nevervflall below that which is maintained in' the supply reservoir l; and the conditions of., uniform andl controlled outbw -tromthe delivery orifice is are more easily established and maintained than'lis possible when the outiiowing'glass' is g subjected to ation of the feeder. This is a diilculty which is al superatmospheric pressure resulting from a forced inward movement of the diaphragm 1 (as contemplated by Hitchcock). 4

The elimination of the forced return stroke of the diaphragm members-which results from the use of a` single acting cam I5 in place of the double acting'cam 2l) of the Hitchcock patent construction-and the consequent-avoidance of any built up super-atmospheric pressure in the chamber 3, (which is also ensured by the supplemental provision of the relief valve I8), has other advantages. If the glass in the delivery chamberis subjected to a superatmospheric pressure, which is too great, or too long continued, the moltenmaterial will be forced'down' below the .top of the supply passage 2, and a portion of the compressedlair will be blown backv into the supply reservoir and create a frothy condition that seriously interferes `with the proper opernot infrequently experienced with many forms of compressed air feeders.

`vAnother advantage of eliminating any compression of .the air in the delivery chamber of my improved apparatus is this: Feeders of the character now under consideration Aoperate on what is known as the closed system principle; i. c., the upper end of the accumulation-delivery chamber and 'the pump chamber connected thereto areintended to form a closed space into .which no air is introduced from an external source, and from which no air is allowed to escape;-the desired changes in pressure in this space being produced only by its successive enlargement and contraction. But this condition is one that itv is very diilicult to maintain; and if oneach compression stroke of vthe pump a small amount of the confined air is allowed to escape (through semi-porous portions of the exposed walls of the delivery chamber (3) or through leaky joints in the pump connection (5) etc.) the vacuum effect -wlll gradually build up and will ultimately lift. the molten material high enough to choke the opening to the pump, and thus -prevent any further operationvof this part of the apparatus. If, on the other hand; air is drawn into the "closed system during the .suction stroke of the pump, the vacuum effect will be reduced, and the expulsion eifecbof the succeeding compression stroke will be augmented. In both cases, therefore, there is an irregularity and consequent uncertainty of action that is detrimental to the uniform long continued operation of the-feeder. In my improved form ot'construction no building up o! pressure in the closed chamr pump space can ever occur, and any gradual diminution of the "vacuum"` eilect can always be at once compensated by an inward adjustment of the washer lock nut elements 2l-2I; and, when the limits of this adjustment have been reached, by a single forced inward stroke' (manually produced) of the diaphragmrod 8.

My invention also differs from the disclosureof the Hitchcock patents in that kI provide an adjustable .gate 2a for controlling the delivery of molten glass from the main forehearth tothe delivery chamber 2. As shown in Fig. II, this gate controls the delivery of glass from the 4two compartments, la and 22, by a vertically adf the chamber 3 and consequently the orice I9 whilethe feeder is not in operation.

I, of course, employ the usual burners or equiv aient heating apparatus to lmaintain the glass w at the properA temperature, both in the main forehearth and in the passage 2 and chamber 3.

In Figs. IV-VIL I have shown a modification of my invention having several other improved features, which are not disclosed or suggested by the Hitchcock patents and which operates on the same principle as the one first described;

i. e., the principle of eliminating or preventing the application of any superatmospheric pressure, or other force, which would supplement the eii'ect of gravity in accelerating the discharge of glass from the delivery orifice.

In this second illustrative embodiment of my i present improvements the tankextension, or

receptacle, which contains the parent supply body of molten glass. differs from the usual form 20 of structure employed for such purposesrin that Y Fig. VIII) or may be readily replaced by another l of diierent depth or form, without altering the main portion of the forehearth assembly. 'One of the important `advantages of this two-part i construction is that it enables me to easily vary -the height, or gravity head, of the glass above the delivery orice-Pand thereby increase or decrease the natural free flow therethroughwithout changing the level of the parent supply body of molten materiallin the main tank exten-` sion, and without altering the degree of lifting action to which the glass above'the orifice is periodically subjected'.

Another advantage of this separable subforehearth arrangement is that it permits of the easy frepair or replacement of vthose parts which 1 -contain and surround the delivery orifice-which is at thelower end ofthe subforehearth chamber)-and which are most subject to the attrition and corrosive action of the outiiowing stream of molten glass.

The main forehearth chamber is divided into justable. gate 22a, whose lower end dips linto the molten pool of glass, and whose upper end is engaged by a pair of angle plates le that rest en the roof of the forehcarth boot, and serve both to support the gate member 22a at any pread- Justed height, Vund to also'seal the openings between the gate block and the aperture through which it passes. Bothof themain forehearth compartments, `la and 22, are heated by two or more suitable burners ua and u; and the latter are preferably so arranged-is` indicated in dotted lines in Fig. VII-as to direct the streamsA of burning'fuel forwardly against the somewhat enlarged semi-cylindrical end of the chamber 22. from which they are deflected and reected backwardly toward the rear compartment la. In order to permit of the free circulation of the. heated gases of combustion through the main foreheartii chamber the gate l22u is provided with l. large port opening 22h, whole lower edge is 75 above the surface of the molten pool of glass, for all positions of the gate and which is of adequate area to provide for the free passage of burned gases from the chamber 22 back into the furnace, and thence to the furnace stack.

The glass delivery orifice Ia is located in the floor of the subforehearth, and is .positioned well below the level of the glass within the delivery chamber 22, for the purpose of obtaining the advantage of a substantial' head of glass over the orifice, and thus obtaining a more rapid natural flow .therethrough than is obtained under normal gravity iiow conditions in the ordinary feeder. In

' order to permit the glass to pass from the chamber 22 to the delivery oriiice -I 9a, communicaltion,'between that ychamber and the orifice, is

established by m'eans of a sleeve 25, which is preferably formed of ceramic material and for structural reasons is preferablycylindrical. The

internal bore 25a of this sleeve is of somewhat greater diameter than the orifice, and its lower end is adapted to receive an orifice bushing 25, which may be removably secured in place by Vany Isuitable meanasuch as a metallic clamp ring andsuitable bolts fol' securing the ring in place.

'Ihe chamber or passageway 25a constitutes a subforehearth chamber and the sleeve 25, within which it is formed, preferably projects above the -upper surface of the refractory lining Id, in the floor of the main forehearth and the delivery chamber 22. 'I'he upper end of this sleeve is however located well below the normal level of4 the Blass within the chamber 22 and its lower DOrtion is surrounded by a refractory block le,

whose inner diameteris greater than the sleeve .f

and which is provided with 'suitable heating means, such as anv induction coil 25b, the terminals 25c of which may be connected to 'any suitable source of electric energy. For the purpose of controlling the flow of molten glass from the chamber 22 to the chamber 25a, I provide an inverted bell 21, which projects downwardly ,through a suitable aperture formed in the roof blockl Il and below the level rounding the bell 21 and projecting downwardly below the level of the molten glass within the chamber 22. As shown, the supporting shoulders of this sleeve and its locking plate 22a are so, arranged that the sleeve may be readily removed for replacement and other purposes.

The bell 21 is provided 'with an internal cavity 21a, which may be termed a segregation chamber; ,and the upper eniof this cavity communicates ivith the e in a tubular bolt 2lb which serves as a metal reinforcement for` the upper portion of the bell structure, ang'zl` may also be employed for the Purpose of securing a metallic cap' 21e to the upper end of the bell. The cap 21c is secured to a hollow coupling sleeve 21d which is, in turn detachably connected to a tubular shaft or spindle that is rotatably mounted in an overhead frame ll.

In the embodiment of my invention illustrated sealing the aperture in the 2,172,895 l in Fig. Iv, the beu 21 is adapted to be rotated..

and also to be vperiodically reciprocated away from and toward the sleeve 25. As here shown,

the shaft member 25 is secured to and carried by a gear 29;` and this gear is supported on a series of rollers in such a manner that as it revolves -it is periodically raised and lowered to impart a corresponding rotary and reciprocatory movement to the interconnected members 2l-21d and 21; this combined movement being guided in part by the roller supports for the gear 2! and in` part by the head frame bearing for the shaft 2l.

The interconnected tubular members 21h-21d and 28 form a continuous passage 21e which leads from the segregation chamber 21a to the upper end of the member 2l; and for .the purpose of controlling and periodically reducing the fluid pressure within the bell 21, this .passageway 21e is connected with the interior of -an expansible and collapsible Sylphonfbellows which is mounted on the gear 29 and revolves therewith.

As here shown, the shaft member 2l extends through the gear 29 and is screw threaded at its upper end for thepurpose of securing it to the gear, and also for the purpose of engaging a flanged 'cap nut 3|, which performs the double function of serving as a lock nut, for the connected elements 28-25, and also as a base plate for the Sylphon bellows. 'Ihe latter is prefer- -ably made up of two corrugated sheet metal cells Ila and 3Ib, that are mounted in, telescopic relationship and are connected in series by means of an annular Z-shaped sleeve llc, one i'iange of which is secured to 4the upper end of the outer Sylphon member ila, and the other ilange oi' which is secured to the lower end of the inner Sylphon member IIb. The outermember lia is hermetically sealed to the cap nut 2| by means of screws which extend through the gear 2l and the flange of the cup nut and engage an annularv base ring Sid on the lower end of this member.

The Sylphon elements ila and Sib are both preferably secured to the flanged sleeve lic by means of brazing or welding, and the base ring Sid is similarly connected to the element Ila. A head piece Sie is likewise vsealed to the upper end of theinner Sylphon 2lb. but this head is provided with an outwardly opening vent or relief valve 32, which corresponds in function to thev valve I8 of the first described embodiment. In order to complete communication between the .segregation'chamber 21a and the interior of the compound Sylphon--il e., the chamber tlf-the cap nut 3| is provided with a series of apertures, Il', which communicate at their lower end with the passage 21e and at their upper end with the chamber III.

'Ihe variation in volumetric capacity of the chamber'Ilf is accomplished by expanding and 4 contracting the Sylphon or bellows elements Ila and lib. The arrangement is however such that while an expansion of the bellows members (i. e., an enlargement of the chamber Il!) occasions a reduction in the ai'r pressure above the glass in the segregation chamber 21a, a contraction oi these members does not' increase the pressure in the chamber 3U or in the sregation chamber 21a above atmospheric pressure. This is due to the fact that I employ the relief valve I2, which,

4as here illustrated, consists of a nicely balanced verticaiap valve so arranged that it will open, and establish communication between the interior of the chamber tlf and the external air, as soon as the pressure in that chamber exceeds atmosvbellows e1 y l the shaft 35; and that the lobe is so formed that the head piece is very quickly raised and is -held pheric pressure. The arrangement is also such that the valve will close normally and will be held closed by the external "atmospheric pressure when a vacuum or partial vacuum is created within the Sylphon chamber 3U.

Periodic variations in the volumetric capacity.

of the chamber 3If'are` effected by means of a cam actuated bell crank lever 33which is pivotally supported on a suitable bracket `of the head frame 30 and whose bifurcated end is adjustably vcoupled tothe head piece, 3Ie, by means of a .threaded pin' 33a and spherically faced nuts 33b` which provide what. is in effect, a ball and socket joint between the engaged parts. For the purpose, of guiding the reciprocations of the head piece, a pin 3io is secured thereto and projects downwardly through the chamber 3l! and into a guiding aperture formed within the cap nut 3|.

The bell crank 33 is actuated by a cam 34 mounted on a shaft 35 whichls driven by any suitable source of power, preferably a variable speed motor. As shown the cam, engaging arm of the bell crank 33 is provided witha cam roller 33'. For the purpose of varying the point of engagement ofthe cam with the cam arm-and thereby changing the corresponding throw of the latterthe roller 33' is of considerable length,

and the cam 34 is so mounted on the shaft 35 that it can be shifted-up and down thereonand thereby move the point of contact between the cooperating elements 33 and 34` either closer to or farther from the fulcrum point of the bell crank 33;-thu`s varying the range of movement imparted to this member (33) and to the connected bellows elements 3Ia-'3 lb.

In order to accomplish longitudinal adjustment -of the camvalong its .operating shaft 35, I have provided a forked shift block 36 which is slidably mounted in suitable guides on the head frame 33,

.and which is provided with projecting arms that engage opposite ends of the cam` and thus determine its position on the shaft 35.

, It will, of course, be understood that the guides for the block 36 arefparallei to the shaft 35, and that a spline 35a or similar means is provided for locking the cam against rotational movement, relatively to the shaft 35, and at the same time permitting its movement along the shaft. The

block 36 is secured in any desired position by a l cap bolt 36a which passes through a slot in the frame 30 and is threaded into the said block.

The cam roller 33' of the bell crank is yieldingly held against the cam 34, by means of com, pression coil springs 33e which are interposed between the head frame 30 andthe outer ends of connecting rods 33d that are coupled to the lower arxn of the bell crank 33.` It will be noted that the cam 34, like the cam I5,is a one lobed single actingA cam (se Fig.y V) which can only act to lift the head piece 3Ie-and thereby expand the ts-once for every revolution of in elevated position for only a relatively short part of each revolution of the shaft 35.

`Froni the foregoing `description, it will be ap- I parent that the cam 34. acting through the bell crank 33, expands the Sylphon members 3'!a and.

3io yonce during each revolution of the shaft 35 thus increasing the internalylume of the chamber 3U and' consequently decreasing the fluid pressure within that chamber vand within the of travel of the cam and that therefore the reduction in pressure within the chamber 21a is maintained for an appreciable period of time or as will be hereinafter pointed out for approximately one fourth of the complete cycle of operation of 5 the feeder mechanism. l.

As the cam lobe moves out of engagement with the roller 33', the springs 33c are left free to act on the bell crank lever 33, and permit the latter to rock .in a counterclockwise direction, as the lo head 3Ie is moved downwardly by the excess atmospheric pressure on the exterior thereof. But the tension of these springs is insuilicient to produce anyforced compression of the bellows elements 31a-3th, #and even if any such forced 15 compression should occur any increase in pressure in the bellows chamber3lf is prevented by the automatic opening of the vent valve 32. 'I'he glass in the segregation chamber 21a can therefore never be subjected to any superatmospheric pressure.

It will be apparent ythat a reduction in the fluid pressure within the chamberk 3U, and consequently in the chamber 21a, will occasion a flow of glass from the chamber 22 into the segregation chamber'21a providedthe relationship between the lower end of the bell and. the upper end of the sleeve 25 is such as to permit such a flow, and as before stated, I have provided means for reciprocating the bell towardand away from 30 the sleeve 25, and this means is so arranged that the sleeve is in its uppermost position at the time that the pressure within the chamber 3l! and the segregation chamber 21a is reduced by the operation of the cam 34. Under such conditions, 35 a free flow of molten glass from the chamber-22 and into the segregation chamber 21a is obtained when the last mentioned chamber is subjected to sub-atmospheric pressure.

As previously explained, the bell 21 is sup:l o ported bythe gear'29 and is rotated by' that gear. The reciprocating motion of the bell is also auto matically imparted thereto by the rotary movement of the parts in the following manner:

.As shown in Figs. IV and VI, the gear mem- 5 ber 29 is supported on'the head frame 30 by means of rollers 31 which are journaled therein and which are engaged with an annular cam track 23a that is detachably secured to the toothcarrying ange of this member. 'I'he roller en- 50 gaging`face or edge of the cam track 29a is provided with alternate lobes 23hv and depressions 23c so located, with respect to the sup- .porting rollers 31, that the gear 29 and consement is further. such that the liftingl of the bell y is synchronized with the periodic reduction in fluid pressure, within the bell chamber 21a which 65 isoccasioned by the expansion of the Sylphon chamber 3U, and the lowering of the bell is approximately coincident lwith the release of the cam roller 33' vfrom the cani 34. 'I'he pressure on the molten glassuwithin' the segregation cham- 70 boris therefore reduced,l by. the positive upward movement of the Sylphon head 31d, while the bell occupies its highest position and the annular -port between its lower end and the top` of the sub-forehearth' sleeve 25 is wide open. 75

As previously stated, the arrangement of the ,cam lobes 29h, with relation to the gear supporting rollers I1, is such that the gear 29 and the bell 21 carried by itV drop to theirlowermost position concurrently with, or inmediately after, the disengagement of the cam elements 3I'-\34, and the head piece lid begins to move downwardly in response to the external pressure of the atmosphere therein. This collapsing movement of the Sylphonl bellows elements almost im' mediately restoresthe pressure in the interior of the bell-i. e., the segregation chamber 21a-to that of the external atmosphere; -and the mass of glass trapped therein (by the downward move- ,ment of the bell) then flows from the delivery orifice under the action of gravity alone.

When the glass within the bell is ilrst sub- -jected to a reduced or sub-atmospheric pressure,

there is a tendency to momentarily check or retard the outow of glass from the delivery orice; and this tendency can be controlled and varied to a considerable degree by changing the phase relationship between the cam elements 29h and Il, and also by increasing or decreasing the depth of glass above the orifice. If the phase relation of the elements (29h and 3l) is so adjusted that the Sylphon bellows is expanded-- in whole or in part, before the bell is raised to establish free communication between the chambers 22 and 25a, the retractiveiniiuence of the partial vacuum in the still trapped mass of glass in the segregation chamber will 'be a maximum and may occasion a very marked retardation or even a momentary' reversal, of the outflow of the glass stream. But if the bellmember is raised, to fully open the inflow'port between its lower end and the adjacent sleeve 25, before the lglass therein is subjected to the reduced pressure,

chamber (on the outflowing stream of glass) may be further minimized, or if desired almost elimi-v nated,by increasing the depth of the sub-forehearth 2b--and thereby increasing the vgravity head or gravity pressure on the glass above the delivery orlilce-so that the ratio between the retarding and the extrusion forces is greatly decreased.

The increase in the depth of the sub-forehearth also diminishes the percentage change in the gravity head at diil'erent stages of the outflow, and thereby tends to maintain the rate of discharge from the delivery orifice-and the resultant diameter of the outowing stream--more nearly uniform.

When the extruded stream of material is to be periodically cut, to form a series of mold charges, the shear` or other cutting elements (38) which are employed for that purpose are preferably placed in close proximity to, but Iout of Vcontact with, the delivery opening (as shown in'Figs. I and IV): and are generally operated to sever the flowing material at the time when the glass in the segregation chamber is exposed to the ryduced (sub-atmospheric) pressure, and there isA a. more or less'pronaunced neckingv of. the

stream flow. Under such conditions, the complete cycle of feeding operations is as follows:

Immediately upon the severance of a charge the bell 21 and its carrying gear 29 areV moved upwardly thus establishing a condition of free flow between the chamber 22, the segregation chamber 21a, and the sub-forehearth chamber 25a and the Sylphon bellows isv concurrently expanded to reduce the pressure therein. As a result molten glass moves freely into the segregation4 chamber and the level to which that glass will be lifted above the level of the glass within the chamber 22 is determined by the degree of vacuum established by the forced expansion of the bellows chamber 3U. The lifting of the bell also increases the discharge through the delivery orice I9a because of the free communication which is then established with the parent body of glass in the chamber 22. As soon as a sumcient quantity of glass has entered the segregation chamber 21a the bell 21 is permitted to move downwardly;

and immediately thereafter atmospheric pressure is against re-established within the Sylphon chamber 21j and consequently within the segre,

gation chamber 21a (by the collapse of the bellows elements Sla-Sib). with the result that the further fiow of material from the oriilce Ila will be' under the head of glass that is now trapped in the interior of the bell and sleeve members 21 and 25. This gravity discharge ofthe molten material is continued until a suiliclent quantity has been delivered to form the requisite mold charge, which is then severed as before during the next application of sub-atmospheric pressure to the glass above the delivery oriilce. This completes one cycle of feeding action. It will.- of course, be understood that it is not desirable to allow the lower end of the bell to come into contact with the upper end of the sleeve 25; but it is advantageous to move the bell as close to this sleeve as is permissible in order that the expelling force of the head of glass contained withinthe'segregation chamber will not be materially reduced by creating an appreciable back ilow from this chamber into the body of material in the main forehearth.

In the illustrative construction shown in Fig. IV, the head frame 30 ls mounted on a plurality of posts 39preferably three-each of which is supported by the forehearth structure and each of which is so arranged that its length-(above its supporti-may be adjusted for the purpose of leveling and also adjusting the height of the head frame. As there shown, the lower end of each post 39 is loosely mounted in a suitably apertured block 39a, and is threaded to engage a capstan nut 29h, which is supported by the block 39a, and constitutes an adjustable support for' the post. This arrangement provides means for either tilting the frame 80 (to bring the bell 21 into axial alignment with the sleeve 2l), or of raising or lowering it to controlthe maximum and minimum opening of the annularport between the members 2i and 21. I have also provided a turnbuckle bolt connection lll b etween the head frame and the forehearth structure for the purpose of locking the head frame in the desired position after the proper adjustment has'been' made by the capstan nutsrllb.

It wil. be apparent that it is desirable to occasionally adjust or vary the vertical height of the ture in Figs. IX and X which facilitates this vertical movement of the head frame and makes it possible to adjust it during the operation of the feeder and without running the chance ofl disturbing the axial alignment of. the members 21 and 25. v

The construction illustrated in Figs. IX and X is in the main similar tothat disclosed in Fig. IV exceptV as respects the mounting for the gear supporting rollers. In this modification, each such.

roller 31 is journaled in a saddle 4I that is provided with a screw threaded shank lla, which is slidably but non-rotatably mounted in guideways 'on the head frame 30' and which are engaged by a worm gear nut 4Ib that is held against longitudinal movement in recessed portions of these guideways. lThere arevtwo of these supporting rollers and saddle supports which are arranged atA tliametrically opposite points in the periphery of the cam ring 29a, and the worm gear nuts Ib are cross connected by a wormshaft 42a so that the two gear wheel supports may be simultaneously raised or lowered by turning this shaft. With this arrangement, the position of the befll 21 with relation to the sleeve 25 (Fig. IV) may be easily adjusted at any time during the operation of the. feeder, and 'without interfering with the position of the head frame 30.

The supporting posts 39 for the head frame 30' may in this case be rigidly attached to the forehearth post; but the upper threaded ends of these posts are connected to the frame by means of the -nuts 43 which are positioned on opposite sides of suitable flanges thereon, and which may be employed both in the alignment .of the bell and sleeve members 21 and 25 and in clamping the parts in ,adjusted position.

,In Fig. IX, the gear member 29 is shown in its lowered position (with the supporting rollers 31 engaging with the depressed portions 29c of the cam track 29a) and the Sylphon bellows (Sla- 3Ib) which is mountettion the upper face of that gear, is collapsed with the valve 32 slightly opened` for the purpose of establishing communication between the chamber 3If and the atmosphere. Iii-this connection, it may be stated that if it is desired to forcibly open this valve at this stage in the cycle of operation (supra), such an action can be readily effected by increasing-the tension of the adjustable take up springs 93e, to such a' degree as will enable them to exert a positive `,compressive force on the collapsing bellows and thus momentarily raise the ,pressure therein slightly above that of the outside air. In order to localize and .concentrate the effect of this momentarily. increased internal pressure on the .relief v'alve 32'(and substantially eliminate any 4con,- current effect o`n the glass in the segregationr chamber V21m-I have provided a light gravity controlled check valve 44, whichis adapted to seat on a shoulder on the member 28 and-which,

is provided with a valve stem which extends up"` wardly into a guiding aperture inthe linger 3Ig. This valve is easily liftedfron its seat by any reduction in pressure within the chamber 3U, but

- is immediately lclosed when the pressure therein exceeds that in the chamber 21a. 'I'his valve is,

however, preferably provided with-one or moreV v of free gravity discharge 'of the trapped or segregated mass of glassv from the segregation chamber.

In operating the type of' feeder herein disclosed-which may be descriptively designated as a periodically actuated. natural flow! `feeder-- molten glass ofthe desired temperature is delivered from a tank furnacel or any other suitable source of continuous supply. to the forehearth .chamber I or Ia the gate (2a or 22a) is adjusted to such a positionl as will cause it to operate both as a supplementary control element and as a skimmer block. The operating shaft (I6 or 35) isy driven at such a speed as to produce the desired number of mold charges, (stream sections) per' unit of time-(viz. one for each revolution of the said shaft) -and in its rotation-xit effects successive periodical expansions ofa bellows member (1 or Bla-SID) which' result in the establishment of a sub-atmospheric pressure,

, or partial vacuum, inthe segregation `or accumulation chamber (3.01' 21a) and in a resultant acceleration of the inflow of glass thereto which is accompanied by a more or less pronounced retardation of the outflow of glass from the delivery orifice (I9 or I9a). As soon as a sumcient quantity, of glass has been drawn into the segregation chamber by the forced expansion of the bellows member (1 or Sla-SIb) the latter is'released and permitted to collapse under the external pressure of the atmosphere; and the glass in the said chamber is expelled from the delivery orice (I9 or I9a) under the action of gravity alone;provision being made for positively pre- .venting any application of super-atmospheric all of the characteristics that distingmish the operation of natural flow feeders, but my present improvements present the additional feature of periodically varying the gravity head (force) under which `this, natural ow is maintained, by

regularly recurrent applications of a lsubatmospheric pressure to the mass of glass above the delivery orice. 'And -as has been previously pointed out. I have also made provision which enables me to vary and control,A within wide limits, the retarding or checking eect of this periodically applied partial vacuum, on the discharge of the molten material during the accumulation period; or, more broadly stated, to vary and regulate the relative effects of the sub`l after ythe severance of the stream by a suitable' shear mechanism-by an unassisted` or 4 natural gravity flow from a mass of glass previously accumulated aboye the delivery orifice. (b) Continuixigthe forniationofl the l'charge under a gradually decreasing gravity head, while" preventing any application of a superatmospheric pressure, or `any other extraneous force, which may act to accelerate or modify the natural gravity 'ow,

this mass above that of the parent body, and

concurrently retarding or checking the outflowing stream, to a greater or less degree.

(e) severing the stream` issuing fromthe oriilce during thismomentary checking or reversal of ow therefrom.

As respects the organization shown in Figs. IV,

V, VI, VII, IX and X it will be further apparent Y. that the apparatus theredisclosed also presents the following additional characteristics of construction and operation, to wit:

(f) A material and controllable increase in the gravity head (pressure) which is `eilective in establishing and maintaining the natural flow,

1 from the delivery oriilce (Ila) ;-this increased controllable effect being obtained;.by the use of subforehearths (la) of varying depth.

(n) Ai material decrease in the percentage change of the gravity head during the continuance of mold charge formation.

(h) A more effective utilization of the increased gravity head that is produced by the accumulation of glass inthe segregation chamber (21a) by the action of the periodically applied subatmospheric pressure;-due .to the prevention of any material hackilow to themain supply chamber, by the lowering of the bell 21, and the substantial closure of the annular port opening between the adjacent ends of the members 21 and 2l.

(i) A regulatable-and when desired a'material-reduction in the eect of the periodically applied sub-atmospheric pressure in the discharge of glass from the delivery orice, Ilmproduced in part by changing the relative areas of the in-v flow port opening (between the sleeve 25 and the raised bell 21, and the outflow opening (lla) and in part by the variable vertical distance between these two openings.

(i) The easy regulation of -the rate of discharge from the delivery orifice, without interrupting the continuous operation of the feeder,

either (1) by, bodily raising or lowering the head frame Ill which supports the rotating and reciprocating bell member 21. and thereby varying the maximum and minimum'areas of the inflow passage from the chamber 22 to the accumulation chamber 21a. (as compared to the area of the delivery opening Ila); or (2) byrmoving the cam 34 along the shaft 2i and thereby changing the expansion stroke lof the Sylphon bellows tia-lib; or (3) less readily. by regulating the supply of fuel to the heating burners for the main forehearth. and the flow-of current to the' heating coil 251i for the sub-forehearth, and

thereby varying the temperature. and `the resultant visoosity of the molten glass.

(k) A more rapid anni perfect equalization vof any temperature orptheryariations in the-body of glass in the main supply-chambers (la and 22) because of continuous stirring action of the 4revolving bell 21. and alsobecause ofthefree circulation of the heating gases through these chambers. A

(l) Asubstantial decrease in the loss of heat from th'e forehearth chambers: ist. because of the eifectiv'e sealing ofthe roof openings through which the memberrlla and 21`pass (bythe 'envases cup andsleeve members Ic and 28); and 2nd, because of the decreased absorption and radiation of heat by and from the highly polished inner and outer surfaces of the sheet metal boots which form the outer walls of the forehearth assembly.

(m) A more effective and reliable control of the sub-atmospheric pressure applications, which is secured by substituting an imperforate hermetically sealed Sylphon bellows vpump for a flexible diaphragm (or reciprocating`v piston) pump; and a substantial increase in the maximum range f -volumetric capacity variations (i. e., in the gree of sub-atmospheric pressure attainable) by the use of telescoping arrangement of the Sylphon elements 2l, Sla, 2lb.

It will also be apparent that the changes in the operation conditions above outlined may be further supplemented by changing the form and relative proportions of various parts' of the apparatus; e. g., by using oriilce bushings (2b) with varying sizes of delivery'openings (Isa):

or by using cams Il of different peripheral contour, (to change the rate o r speed of expansion movement of the bellows 2id-Sib) or by altering the phase setting of the cam 34 so as to change the relative times of expanding the bellows member and of raising and lowering the bell 21 (for the purposes alneadyexplained); or by providing any well known form of shear actuating mechanism (not here shown) which can be operated in any desired time relationship to the moving parts of theapparatus herein described. It is further obvious that the mass or volume of the successively formed and severed stream sections (mold charges) may be readily controlledindependently of all other means above described-by varying the speed (R. P. M.) of the main driving shaft 35. l

The type of feederwhich I have here disclosed is capable of and adapted to, the production of successively delivering mold charges of widely varied form, or cross sectional contour, and

Aweightbutin using this feeder I prefer to so v.proportion and control the action of the cooperatingpartsastomakethesechargesasthick and as short (i. e., as chunw" in form) as is permitted by the sise'of the opening in the While I have only described in detail one specic series of steps in the formation and delivery of successive mold` charges those skilled in the art will now'readily :appreciate that ,various changes in the procedure outlined by me-and various changes in. additions to, and omissions from, the apparatus here illustrated as suitable therefor-may be made without departing from the 'spirit and scope of my invention and I desire it to be understood that I -have' designed various feeder mechanisms and various feeding pro'- cedures for feeding molten glass in a continuously flowing pulsating stream and that such mechanisms and procedures form the subject matter of and are claimed in copending applications for Letters Patent and structurally and functionally distinguish from the features herein claimed.

What I claim as new and desire to secure by Letters Patent is:

1. A feeder for molten glass` comprising areceptacle for molten glass having an orifice formed in the bottom thereof, a chamber located within said receptacle extending above said orifice and communicating with said receptacle and said ori-y fice, means for periodically exhausting said chamber to a sub-atmospheric pressure and a check valve communicating with the atmosphere for preventing the fluid pressure within said chamber exceeding atmospheric pressure.

2; A feeder for molten glass comprising a re- 4 ceptacle for molten glass, having a delivery orifice formed in the fioor thereof, an inverted bell substantially aligned with said orifice and projecting below the surface of the glass contained within said receptacle, means for rotating said bell, means for periodically reciprocating said bell toward and away from said orifice, means operating in synehronism with said last mentioned means for periodically exhausting the interior of said bell to a sub-atmospheric pressure, and a -one way valve :communicating with the atmosphere and the interior of said bell for preventing the fiuid pressure within said bell exceeding atmospheric pressure.

3. A feeder for molten glass comprising a receptacle for molten glass, having an orice formed in the fioor thereof, an inverted bell projected downwardly into said receptacle and below the surface of the glass contained within said receptacle and aligned with said orifice,

means for rotating said bell, means for periodically moving said bell away from said orifice, means for subjecting the interior of said bell to sub-atmospheric pressure as said bell moves away from said orifice and means for preventing the viiuid pressure within said bell exceeding atmospheric pressure.

4. A feeder for molten glass comprising a receptacle for molten glass, having an opening formed in the floor thereof, a sub-forehearth communicating with said opening and -having a delivery orifice formed in the lower end thereof,

^ located within said receptacle. aligned with said orifice, and projecting below the surface of the glass contained within said receptaclea compound Sylphon communicating with said chamber, means for periodically expanding and contracting said Sylphon and means for preventing the uid pressure in 'said chamberl exceeding atmospheric-pressure during' periods of contraction of said Sylphon.

6. A feeder for molten glass, comprising a receptacle for molten glass, having an opening formed in the bottom thereof, a sub-forehearth removably secured to said receptacle and communicating with the interior thereof through said opening, means for heating said ,sub-forehearth, and means located wholly above said sub-forebearth for controlling the delivery of glass from said receptacle to said sub-forehearth.

7. A feeder for molten glass, comprising a receptacle for molten glass, communicating with a molten glass-submerged delivery orifice, an inverted bell extending into said receptacle and aligned with said orifice, means for rotating said bell, a compound Sylphon communicating with the interior of said bell, an atmospheric relief valve communicating with said Sylphon, a check valve located between said Sylphon and said bell and means for periodically expanding and contracting said Sylphon,

8. In a feeder for molten glass, an inverted bell aligned with the flow orifice ofsaidfeeder, means for rotating and reciprocating said bell, means for adjusting the position of said bellv above such orifice, adjustable means for subjecting the interior of ysaid bell to sub-atmospheric pressure and a one way valve communicating with the atmosphere and the interior of said bell for preventing fiuid pressure in said bell exceeding atmospheric pressure.

9. In combinationI in a glass feeder, a receptacle for molten glass communicating with a source of molten glass and provided with a submerged iiow orifice, an adjustable gate for controlling communication between said source and said receptacle, an inverted` bell extending into said receptacle and aligned with said orifice, means for periodically subjecting the interior of said bell to sub-atmospheric pressure, a one way valve communicating with said chamberand the atmosphere, and means for rotating and reciprocating said bell.

10. In combination in a feeder for molten glass, a reeeptaclefor a body of molten glass having an orifice formed therein adapted to be submerged by glass contained therein, a segregation phamber located within said receptacle, means for periodically subjecting the interior of said chamber to variations in iiuid pressure,'

comprising telescopically mounted Sylphon members enclosing a chamber of variable volumetric capacity, means for expanding and contracting said members, means for varying the degree of, expansion of such members, a shear mechanism located below said .orifice and means operating in synchronism with said Sylphon expanding means for actuating said shears.

11. In combination in a feeder for-molten glass, an inverted bell located above Aand aligned with the flow orifice of said feeder, and means for rotating and reciprocating said bell, comprising a gear supporting the bell, an annular cam track secured to one face of said gear, a series of'rollers supporting said cam track said gear and inverted bell, means for rotating said gear and means foradjusting the position of saidA cam track.

12. In combination in a feeder for molten glass, an inverted bell located above and aligned with theflow orifice of said feeder, means for rotating and reciprocating said bell, comprising a gear supporting said bell, a cam( track secured to the under face of said gear, a series of rollers of heating gases around said bell, through said forehearth and into said tank to thereby assist in maintaining a uniform temperature of the glass within said forehearth.

14. In combination in a feeder for molten glass, a forehearth, a tank communicating there- I forehearth and adjacent said bell to the external air.

15. In combination in a feeder for molten glass, a receptacle for molten glass having an orifice formed in the bottom thereof, a subforehearth detachably secured to said receptacle, extending below the bottom thereof and having an open ended passage communicating with said orifice, an orice bushing removably mounted in the lower jend of said passage and means lo'- cated within said receptacle` and wholly above said sub-forehearth for controlling the flow of glass from said receptacle through said bushing.

16. In combination in a feeder for molten glass, a forehearth comprising a receptacle for molten glass having an opening formed therein below the normal level of the glass contained there a sub-forehearth removably secured to said orehearth extending below the bottom thereof and having an open ended passage with one end communicating with said opening and the other end constituting .a delivery orifice, an oriflce bushing removably mounted in the orifice end of such passage, shears located below said sub-forehearth, means for applying heat to molten glasstraversing said passage and meanslocated within said receptacle and above said subforehearth for vcontrollingrthe delivery of glass through said delivery orice.

17. A method of forminga succession of separate mold charges from a body of molten glass. which consists in occasioning a gravity flow oi' molten glass through an orifice and from a body of such 'glass submerging such orifice, momentarily reducing such flow while accumulating a mass of such glass from such body and above said orice, simultaneously severing the stream of glass issuing from the orifice at a point below but adjacent to said orifice, restricting the ilow from said body to said orifice while establishing a flow through said orifice under the gravity head of said mass alone and while preventing the application of an expelling force, other than gravity, on the glass of said mass, removing such restriction between the body and the o'riiice and then repeating the cycle to produce a succession of mold charges.

18. The method of feeding molten glass, which consists in causing glass to ilow from a bodv of molten glass through a submerged orifice, applying sub-atmospheric pressure to the surface of vthe glass above the orifice to accumulate and segregate a mass of glass from said body above said orifice, severing the stream of glass issuing from the orifice at a plane adjacent .the orifice and during the` period of such accumulation, establishing a gravity flow from said mass through said orifice while adjustably restricting communication between said mass and said body, and then repeating the cycle to form a succession of mold charges.

19. In combination in a feeder, a container for molten glass, a forehearth communicating therewith-and having an enlarged substantially semicylindrical forward end with a glass delivery oritice formed in the bottom thereof substantially concentric with the semi-cylindrical portion thereof, an inverted bell extending downwardly into the glass within said forehearth and substantially axially aligned with said oriiicefand means for establishing and maintaining a balanced symmetrical flow of heating gases through the semi-cylindrical portion of said forehearth and around said bell, to thereby assist in maintaining a uniform temperature of glass within said forehearth. l

20. The method of feeding molten glass which consists in establishing a ilow of molten glass from a supply body and through an open ilow orifice under a predetermined gravity head, periodically raising the level of the glass over the orifice above the level of said supply body to increase the head of glass over the orifice while maintaining the flow therethrough from the supply body, and then restricting the flow from said supply body to said orifice while utilizing such additional head to increase the flow through the orifice.

21. The method of feeding molten glass which consists in establishing a flow of glass from a supply body and through an open flow oriiice under a predetermined gravity head, periodically applying suction to the glass over the orifice to increase the gravity head thereover and while maintaining the ilow from said body through said orifice, restricting the flow from said body to said orifice while utilizing such increased head to vary the ow through the orifice, removing such restriction to re-establish the iiow from said body through said orice, and periodically severing successive mold charges from the stream of 4glass issuing through said orifice.

FRANK L. o.y wADswoR'rH. 

